Botryllophilus antarcticus Kim & Boxshall 2021, sp. nov.

• Main Authors: Kim, Il-Hoi, Boxshall, Geoff A.
• Format: Other/Unknown Material
• Language: unknown
• Published: 2021
• Subjects: Biodiversity; Taxonomy; Animalia; Arthropoda; Maxillopoda; Cyclopoida; Ascidicolidae; Botryllophilus; Botryllophilus antarcticus; Antarctic; The Antarctic; Terre Adélie; Terre-Adélie; Antarc*; antarcticus
• Online Access: https://zenodo.org/record/5582586; https://doi.org/10.5281/zenodo.5582586

Botryllophilus antarcticus sp. nov. (Figs. 33- 35) Type material. Holotype ♀ (MNHN-IU-2018-1958, dissected and mounted on a slide) from Aplẚdẚum falklandẚcum Millar, 1960 (MNHN-IT-2008-386 = MNHN A1 / APL.B/532); Antarctic, Terre Adélie, CEAMARC cruise, RV “Aurore Australis”, Stn 18EV479 (66º10’S, 139º41’E), depth 402-437 m, IPEV-AAD-MNHN coll., 15 January 2008. Etymology. The name of the new species is based on its type locality, the Antarctic. Description of female. Body (Fig. 33A) fleshy with thin exoskeleton; length 1.58 mm. Anterior part of body unsegmented; cephalosome recognizable from metasome only by faint dorsal constriction. Narrower posterior part (Fig. 33B) comprising genital somite and abdomen consisting of 5 indistinct annulations. Genital somite 170×250 μm, obscurely defined from fifth pedigerous somite; genital apertures positioned dorsolaterally. Abdomen gradu- ally narrowing posteriorly; first to fourth abdominal annulations subequal in length; fifth (anal somite) 77×115 μm, distinctly wider than long. Caudal rami divergent; each ramus (Fig. 33C) about 1.4 times longer than wide (54×38 μm), armed with 4 claws and 2 setae; all caudal claws pointed at tip, longest claw straight, 48 μm long, as long as caudal ramus. Rostrum absent. Antennule (Fig. 33D) stout, 195 μm long, 4-segmented, but terminal segment subdivided by incomplete suture on one surface; first and second segments expanded, incompletely articulated from each other; armature formula 9, 5, 2, and 11+aesthetasc; all setae naked. Antenna (Fig. 33E, F) 4-segmented; coxa, basis, and first endopodal segment unarmed; second endopodal segment 4.7 times longer than wide, armed with 3 spines on inner margin and 5 setae on distal margin. No difference recognizable between right and left antennae. Labrum (Fig. 33G) simple, nearly semicircular. Mandible (Fig. 33H) with 3 teeth on coxal gnathobase; palp with 9 setae, grouped as 3, 2, 2, and 2. Maxillule (Fig. 33I) consisting of precoxa and palp; precoxa with 6 setae on arthrite, minute second ...